The present invention relates to an electrical connector, more particularly to an improved electrical connector including a terminal engagement holder for preventing the terminals of the connector from inadvertently being removed rearwardly from the housing of the connector after being inserted into the terminal chambers of the housing.
An electrical connector includes terminals, terminal chambers, and engagement means which are so-called terminal lances or case lances provided on the terminals or the chambers in order to prevent the terminals from inadvertently being removed rearwardly from the chambers after being inserted into them. Each of the terminal lances is formed by cutting and bending a portion of the terminal, and engaging that portion in an engagement groove provided in the inside surface on the terminal chamber. Each of the case lances is a flexible engagement arm provided on the inside surface on the terminal chamber, and engaged with the shoulder of the terminal or in the engagement opening thereof. However, such a terminal lance and such a case lance have become smaller in size along with the increase in the number of the terminals of such an electrical connector or the reduction in the size of the terminal so that it has become difficult to maintain the strength and holding power of the lances sufficiently high. For that reason, a terminal engagement holder manufactured separately from a housing has recently been used along with such engagement means to increase the terminal holding power of an electrical connector to enhance the reliability of electrical connection thereof.
FIGS. 12A and 12B show a conventional electrical connector including such a terminal engagement holder b and disclosed in the Japan Patent Examined Publication No. Hei. 1-43986. The holder b is tentatively engaged with the housing a of the connector as shown in FIG. 12A, and is thereafter engaged with the housing on a full scale as shown in FIG. 12B. While the holder is in the-tentative engagement with the housing a, terminals are inserted into the terminal chambers a.sub.1 of the housing so that the engagement portions c.sub.1 of the terminals are engaged with the terminal engagement claws a.sub.2 of the housing to subject the terminals to primary engagement holding. The holder b is thereafter engaged with the housing a on a full scale so that the edges b.sub.1 of the holder are engaged with the terminals c to subject them to secondary engagement holding.
Since the terminal engagement holder of the above-mentioned conventional electrical connector has a butting corner portion b.sub.2 for preventing the holder from being unexpectedly engaged with the housing a on the full scale as the holder is manipulated to be tentatively engaged therewith, shifting the holder out of the tentative engagement into the full-scale engagement requires two steps of manipulation, which are a step of moving the holder sideward in a direction p, and another step of thereafter moving the holder forward in a direction g. This is a problem of less efficiency. Besides, the terminal c is likely to be slightly longer than a prescribed length due to the elongative caulking of the electric wire connecting portion c.sub.2 of the terminal, the dimensional error of the terminal or the like so that the rear end c.sub.2 ' is located behind a prescribed position, as shown by a two-dot chain line in FIG. 12B, to make it impossible to lock the holder b to the housing a. Further, the holder b needs to be in the full-scale engagement with the housing a when the connector is fitted with another electrical connector for their mutual electrical connection. However, because of the constitution of the conventional connector, it is necessary to confirm by eyesight whether or not the holder is in the full-scale engagement with the housing a. The confirmation is troublesome requiring a high degree of care. Furthermore, if a tensile force acts on an electric wire W in a direction r reverse to the former p and q while the holder b is in the full-scale engagement with the housing a, as shown in FIG. 12B, the holder is shifted out of the full-scale engagement back into the tentative engagement so that the terminals c are no longer being retained in a double engagement manner.